This method is just breaking up the numbers into their tens, hundreds, and so on so that you can keep track of place values when multiplying. In this example,
$$15*23=(10+5)*(20+3)=20*10 + 5*20 + 10*3 + 5*3=200 + 130 + 15$$
So the first digits of each number 1 and 2 correspond to 10 and 20 which when multiply to give the largest place value, the mixed terms are in between and the last digits 5 and 3 give the smallest contribution. So basically, the method is using distributivity and is not very different from other methods. It does nicely keep track of powers of 10.
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According to Wikipedia, "It is not known where it arose first, nor whether it developed independently within more than one region of the world".
This method is just breaking up the numbers into their tens, hundreds, and so on so that you can keep track of place values when multiplying. In this example, $$15*23=(10+5)*(20+3)=20*10 + 5*20 + 10*3 + 5*3=200 + 130 + 15$$ So the first digits of each number 1 and 2 correspond to 10 and 20 which when multiply to give the largest place value, the mixed terms are in between and the last digits 5 and 3 give the smallest contribution. So basically, the method is using distributivity and is not very different from other methods. It does nicely keep track of powers of 10.